Elastic boat, particularly applicable to seaplane floats



- Oct. 13, 1936. R, Hopp 2,057,574

ELSTIG BOAT,- PARTICULARLY APPLICABLE TO SEAPLANE FLOATS Filed March 19,1936 Patented Oct. 13, 1936 UNITED STATES ELASTIC BOAT,

PARTICULARLY APPLICA- BLE T SEAPLANE FLOATS Richard Hopp, Berlin,Germany, assigner to Reginald William Allo Application March 19,

tt, Yorkshire, England 1936, Serial No. 69,703

In Germany April 30, 1935 12 Claims.

This invention relates to elastic boats larly applicable to seaplanefloats.

It is a known practice to construct boats with elastic framework and askin or outer cover made of fabric; in which boats the stem alsoconsists of elastic material, mostly of round or at steel. This steelmust not be too thin otherwise the parts will not possess the requisitestrength; on the other hand, even if the steel is of suitable thick- L0ness, impacts of any great force against the stem will result inpermanent deformation of the latter even when good spring steel is used,because the part struck will be strained beyond its elastic limit sothat such a boat cannot be considered to l5 offer suicient resistance.In order to obtain the desired resistance, it is necessary to distributethe impact over Va fairly large section of the material.

The object of the present invention is to attain this desideratum.

According to this invention, in an elastic boat having a rigid keelframe and a. resilient framework, there is provided in combination astem consisting of a helical spring and a tension member both attachedat their opposite ends to the keel frame and the gunwale of theresilient framework.

A particular embodiment of the elastic boat according to this inventioncomprises a rigid keel frame, a framework consisting of resilient ribs,stringers and gunwale, bow and stern stems each consisting of a helicalspring and a tension member both attached at their ends to the keelframe and gunwale respectively and a flexible skin covering the saidframework.

In a practical construction the stem of my boat consists of a helicalspring of ample dimensions let into the heavy keel frame at one end,while the other end is connected at the stem to the gunwale which ismade of flat spring steel. Between the two end points of said spring atensioning member is provided. The object of this is, primarily, toimpart the necessary curvature of the spring forming the stem.

At the same time, the tensioning member is required in order bypreventing the ends of the spring stretching to their full length and toincrease the resistance of the spring, so as to make better use of itselasticity. Moreover, the tensioning imparts a stable form to the endsof the boat, preventing the point of the boat being pulled out, ashappens in towing, and also preventing the after stem from yieldingoutwards under impacts on the forward part of the vessel. As the 55spiral spring can yield in all directions it is capable of taking uplateral or oblique impactscoming from forward-such as occur particularlywhen landing on rock-bound coasts. Excessive mobility is prevented bythe floorhead stringers 60- which are also of spring steel and are fixedto the particuf (C1. 9 6) springs both at stem and stern by means of asleeve. In order to ensure the utmost possible resiliency of the hull ofthe boat, it is advisable to avoid riveting as far as possible and onlyto ladopt it at the ends of the ribs at the gunwale, while the floorheadstringers may be arranged in duplicate running in juxtapositionalternately, the ribs being worked under and over the ribs in the mannerof adjacent strands of basketwork. The keel frame is very strongly builtup of wood and crosses the ribs which are continuously connected withthe keel in one piece running from gunwale to gunwale. The spring steelmaterial should be as thin and narrow as possible with a view toelasticity. The thwarts are elastically suspended and are designed totake both tension and compression. The outer skin does not, as incollapsible boats, consist of a combined canvas and rubber skin, but ofseparate sheets, namely a fabric sheet inside and outside for protectionand 20 a middle, very elastic, rubber sheet in between the fabricsheets.

The invention will now be described with reference to the accompanyingdrawing in which:-

Fig. 1 is a perspective view of an elastic boat constructed inaccordance with the invention,

Fig. 2 is a section of a stem along the centre line of the boat,

Fig. 3 a section through one of the thwarts,

Fig. 4 is a similar View to Fig. 3 showing an alternative constructionfor supporting the thwarts, and

Fig. 5 is a section of a detail.

Referring to the drawing the stern, which may either be at the bow orthe stern or both, is provided with a helical spring l attached at oneend to the gunwale 2 and at the other end to the end of the keel frame 3as at 4 (Fig. 2). A tensioning arrangement comprising a flexible cableor wire 5 is also attached in a similar manner to the gunwale 2 and thekeel frame 3. The nuts fastening this cable or wire to the gunwale andkeel frame permit the tension of the wire to be varied.

The framework of the boat is completed by means of ribs 6, which passunder the keel frame 3 as will be later described in greater detail, andby floorhead stringers 1, which are each formed of two strips of springsteel running under and over alternative ribs 6 and disposed adjacent toone another in the manner of adjacent strands in a basketwork. Thefloorhead stringers 'l which are attached at their ends by means ofcollars 8 to the helical springs I at each stem, carry the floor of theboat (not shown in the drawing) in conjunction with the keel frame 3.

The gunwale 2, the ribs 6 and the floor head stringers 1 are all made ofstrips of spring steel, which, being both strong and resilient, enablesshocks received by the stem to be absorbed.

The thwarts 9 are carried of spring steel supports I each attached attheir upper and lowerL ends to a rib 6 near the gunwale 2 and near theiioorhead stringers 1. This construction is clearly shown in Fig. 3.

Referring to Fig. 4, an alternative construction for supporting thethwarts 9 shown,-in which the ribs supporting the thwarts 9 areprolonged upwardly and bent over to form a loop Ii,"4 to the inner edgeof which the thwarts 9 are attached.

Such arrangements for supporting the thwarts 9 enable rigid thwarts tobe used since distortion in shape due to shocks received by the stem orthe resilient frame are taken up by the supports I9 or 6a and are nottransmitted to the thwarts.

planking II laid over the ribs 6, which are sup-4 ported by a layer oftransverse planks I2 and a final layer of longitudinal planking I3, thewhole series of planks being bolted together.

enclosing an elastic layer I7, e. g. rubber, is to the framework by 'theplate I8 and nut and bolt I9 shown in Fig. 5.

The boat is suitable for use as a lifeboat on ships, because launchingit, even in a rough sea, will not cause it much damage. In this case,buoyant chambers would be provided which may be located under thethwarts. It can also be used as pilots lboat and landing boat onrock-bound coastsr or for expeditions. It is, however, particularlysuitable for use as a float on seaplanes. v What I claim as myVinvention and desire to secureby Letters Patent is:-

1. In an elastic boat having a rigid keel frame and a. resilientframework, the combination of a stem consisting of a helical spring anda tension member both attached at their opposite ends t0 the keel frameand resilient framework.

2. An elastic boat comprising a rigid keel'frarne,v

a framework consisting of resilient ribs, stringers and gunwale, atleast'one stem consisting of a helical spring and a tension member,means for attaching said spring and, tension member at their andaresilient framework, the combination of a.

helical spring and a length of stout flexible cable,

meansforattaching'said,springend cable at their wale,

opposite ends to the keel frame and the gunwale of the said resilientframework, and means for varying the tension of said cable.

7. An elastic boat comprising arigid keel frame,

, a framework consisting of resilient ribs and gunow and stern stemseach consisting of aV helical 8. An elastic boat comprising a rigid keelframe,

a framework consisting of resilient ribs, stringers and gunwale, bow andstern stems each consistrespectively, iloorhead stringers connecting thebow and stern stem springs, rigid thwarts, a strip framework.

11. An elastic boat comprising a rigid keel frame consisting of a strongkeel beam, a layer of transa helical spring and a attaching both saidstems each consisting of tensionV member, means for spring and tensionmember keel frame and gunwale respectively and a flexible skin coveringthe said framework. Y

12. An elastic boat comprising a rigid keel frame, a frameworkconsisting of resilient ribs, stringers and gunwale, bow and stern stemseach consisting of a helical spring and a tension member, means forattaching both said spring and tension member at their ends to the keelframe and gunwale respectively and a flexible skin consisting of aninner and an outer layerv of fabric enclosing an elastic layer coveringthe said Vframe-` work.

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at their ends to theY iof

